With a development of a modern world, people gradually pay attention to an importance of a personal identification and a personal information security. Since a human fingerprint has uniqueness and invariance, and a fingerprint identification technology has characteristics of good safety, high reliability, use being easy and convenient, and the fingerprint identification technology is widely used in various fields for protecting a personal information security. With a continuous development of a scientific technology, an information security problem of each kind of an electronic product is always one of focus points to a technical development. Particularly for a mobile terminal, such as a mobile phone, a laptop, a tablet, a digital camera, a requirement of the information security is very prominent.
A sensing method of a conventional fingerprint identification device includes a capacitive method (electric field method) and an inductive method. The fingerprint identification device obtains fingerprint information of a user by extracting a user fingerprint and converting the user fingerprint to an electrical signal and outputting the electrical signal. Specifically, as shown in FIG. 1, FIG. 1 is a schematic section structural diagram of a conventional fingerprint identification device which includes a substrate 100, a fingerprint identification chip 101 coupled to a surface of the substrate 100, and a glass substrate 102 covering a surface of the fingerprint identification chip 101.
A capacitive fingerprint identification chip is taken as an example. There is one or more capacitive plates in the fingerprint identification chip 101. As there are a convex ridge and a concave valley on epidermis or beneath the epidermis of a user finger, when the user finger 103 contacts the surface of the glass substrate 102, a distance from the ridge to the fingerprint identification chip 101 is different from a distance from the valley to the fingerprint identification chip 101. So capacitance between the ridge of the user finger 103 and the capacitive plate is different from capacitance between the valley of the user finger 103 and the capacitive plat. The fingerprint identification chip 101 may obtain the different capacitances and convert the different capacitances to corresponding electrical signals and output the electrical signals. After the received electrical signals are converged, the fingerprint identification device may obtain the fingerprint information of the user.
However, in the conventional fingerprint identification device, a requirement of sensitivity of the fingerprint identification chip is high, which limits a manufacture and an application of the fingerprint identification device.